Thermochemical hydrogen production

Since then, laboratories around the world have taken up the research and have collaborated under sponsorship from both the European Commission and the International Energy Agency. Many different cycles have been proposed and investigated here we mention just a few as illustrative of this area of endeavour. 

A typical early process (known as the UT-3 cycle ) was based on the use of calcium bromide. The cycle consists of the following four reactions  

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Multistep Thermochemical Water Splitting. Multistep thermochemical hydrogen production methods are designed to avoid the problems of one-step water spHtting, ie, the high temperatures needed to achieve appreciable AG reduction, and the low efficiencies of water electrolysis. Although water electrolysis itself is quite efficient, the production of electricity is inefficient (30—40%). This results in an overall efficiency of 24—35% for water electrolysis. 

Funk, J.E., Thermochemical hydrogen production past and present, Int. ]. Hydrogen Energ., 26, 185, 2001. 

Onuki, K. et al., IS process for thermochemical hydrogen production, JAERI-Review 94-006, 1994. 

S. Sato (1979) Thermochemical hydrogen production in p. 81-114 Solar-hydrogen energy systems Ed. by Ohta T., Pergamon, Oxford... 

As well as the previously described methods of hydrogen production, there are other commercial processes whose application is restricted to specialised production conditions. These include the partial oxidation of heavy hydrocarbons, autothermal reforming and the Kvcerner process. In addition, there are numerous production processes that are still at the basic research stage, but show promising potential. These primarily include thermochemical hydrogen production, photochemical and biological processes. The main characteristics of these methods are outlined below. For a more detailed discussion, please refer to the relevant specialist literature. 

Different strategies have evolved for thermochemical hydrogen production to effectively utilize the potentials of, in particular, nuclear and solar thermal energy sources. These strategies, which we discuss below, can be categorized depending upon the number of process steps involved and whether electrolysis is employed in a reaction. 

Sato S (1979) Thermochemical hydrogen production. In Ohta T (ed) Solar hydrogen energy systems. Pergamon Press, New York... 

Engels H, Funk JE, Hesselmann K, Knoche KF (1987) Thermochemical Hydrogen-Production. Int J Hydrogen Energy 12 291-295... 

Thermochemical hydrogen production by a redox system of Zr02-supported Co(II)-ferrite. Sol Energy 78 623-631... 

Beghi GE (1981) Review of thermochemical hydrogen production. Int J Hydrogen Energy 6 555-566... 

Tadokoro Y, Kajiyama T, Yamaguchi T, Sakai N, Kameyama H, Yoshida K (1997) Technical evaluation of UT-3 thermochemical hydrogen production process for an industrial scale plant. Int J Hydrogen Energy 22 49-56. 

Mathias, P. M., Brown, L. C., Thermodynamics of the sulfur-iodine cycle for thermochemical hydrogen production, in Proceedings of the 68th Annual Meeting Of the Society of Chemical Engineers (23 March 2003), Japan, 2003. 

Terada, A., et al. (2006), Development of Sulfuric Acid Decomposer for Thermochemical Hydrogen Production IS Process , Trans. Atom. Energy Soc.Jpn., Vol. 5, pp. 68-75. 

Predicting the energy efficiency of a recuperative bayonet decomposition reactor for sulphur-based thermochemical hydrogen production ... 

DEVELOPMENT STATUS OF THE HYBRID SULPHUR THERMOCHEMICAL HYDROGEN PRODUCTION PROCESS... 

Development status of the hybrid sulphur thermochemical hydrogen production process ... 

Naterer, G.F., et al. (2008), Thermochemical Hydrogen Production with a Copper-chlorine Cycle, I Oxygen Release from Copper Oxychloride Decomposition , International Journal of Hydrogen Energy, 33, 5439-5450. 

Suppiah, S., et a1. (2008), Thermo-mechanical Design of Nuclear-based Hydrogen Production , ORF Workshops on Nuclear-Based Thermochemical Hydrogen Production, Oshawa, ON (December 2007) and Chalk River, ON (October 2008). 

Mathias, Paul M., Lloyd C. Brown, et al. (2003), Thermodynamics of the Sulfur-Iodine Cycle for Thermochemical Hydrogen Production , 68th Annual Meeting of the Society of Chemical Engineers, Japan, 23 March. 

If solar heat is considered for a thermochemical hydrogen production process, two additional variables must be considered. 

Materials Development for Sulfur-Iodine Thermochemical Hydrogen Production... 

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